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ARS Home » Plains Area » Mandan, North Dakota » Northern Great Plains Research Laboratory » Research » Publications at this Location » Publication #385752
Research Project: Sustainable Agricultural Systems for the Northern Great Plains

Location: Northern Great Plains Research Laboratory

Title: Do plant secondary metabolite-containing forages influence soil processes in agroecosystems?

Author
item Clemensen, Andrea
item VILLALBA, JUAN - Utah State University
item Lee, Stephen
item PROVENZA, FREDERICK - Utah State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/7/2021
Publication Date: 11/7/2021
Citation: Clemensen, A.K., Villalba, J.J., Lee, S.T., Provenza, F.D. 2021. Do plant secondary metabolite-containing forages influence soil processes in agroecosystems?. Meeting Abstract. 1.

Interpretive Summary:

Technical Abstract: Nitrogen-fixing legumes such as alfalfa (Medicago sativa L.) and sainfoin (Onobrychis viciifolia Scop.) can benefit agricultural systems. In addition to quality forage, both legumes contain secondary metabolites that play important roles in agroecological systems. Alfalfa contains triterpenes (saponins), and sainfoin contains phenolic compounds (condensed tannins). Terpenes and phenolics can influence soil nutrient dynamics by inhibiting microbial activity, which could slow nitrogen mineralization and minimize nitrogen loss. However, research evaluating their influence in soil has largely come from controlled laboratory studies. Therefore, we initiated a field study in Lewiston, Utah, USA comparing two legume systems with a grass system. The split-split experimental design had three replicates and included a fertilized bale and remove system, a green manure system (leaving plant residue in field), and a no-input bale and remove system comparing alfalfa and sainfoin, both of which had a tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] as a grass control. We assessed saponin and condensed tannin concentrations in alfalfa and sainfoin, respectively, and various soil characteristics. Differences in plant biomass and total soil N between legume treatments were negligible (p = 0.40), though soil nitrate was greater in the alfalfa than the sainfoin treatments (p < 0.01). We speculate that differences in nitrate may be due to mineralization inhibition by presence of tanniferous sainfoin relative to alfalfa. Planting forages containing tannins may influence soil nutrient dynamics, allowing producers to enhance the sustainability of their lands by reducing nitrogen loss.